Question: Simplify the following expression: $z = \dfrac{-a}{2} + \dfrac{7a}{2}$
Since the expressions have the same denominator we simply combine the numerators: $z = \dfrac{-a + 7a}{2}$ Combine like terms: $z = \dfrac{6a}{2}$ Simplify by dividing numerator and denominator by 2: $z = \dfrac{3a}{1}$ $z = 3a$